ES2787602T3 - Curable fluorocopolymer formed from tetrafluoropropene - Google Patents

Abstract

A copolymer comprising: (a) a first unit comprising a polymerized monomer selected from the group consisting of 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene; (b) a second unit comprising a polymerized monomer selected from the group consisting of vinyl esters and vinyl ethers; wherein the vinyl esters and vinyl ethers are of the formula CH2 = CR1-O (C = O) R2 and CH2 = CR3-OR4, respectively, where R1 and R3 are hydrogen or a methyl group, and where R2 and R4 is an unsubstituted, branched or straight chain alicyclic alkyl group having 1 to 12 carbon atoms; and (c) a third unit comprising a polymerized monomer comprising a vinyl ether containing a hydroxyl group of the formula CH2 = C-R5-OR6, wherein R5 is hydrogen or a methyl group, and R6 is an alkyl group of unsubstituted straight, branched or alicyclic chain having a hydroxyl group.

Description

DESCRIPTION

Curable fluorocopolymer formed from tetrafluoropropene

Cross reference to related applications

The present application claims priority to US Provisional Application Serial Number 61 / 894,146, filed October 22, 2013, the disclosure of which is incorporated herein by reference. The '146 provisional application is related to the US application. No. 13 / 645,444, filed Oct. 4, 2012, U.S. application No. 13 / 645,437, filed Oct. 4, 2012, of U.S. provisional application No. 61 / 543,780, filed Oct. 5, 2011 and US Provisional Application No. 61 / 543,714, filed Oct. 5, 2011, the contents of which are incorporated herein by reference in their entirety.

Field of the invention

The present invention relates generally to novel curable copolymers formed, at least in part, from tetrafluoropropene. More specifically, the present invention relates to curable copolymers formed in part from monomeric material comprising 2,3,3,3-tetrafluoropropene (c F ^s CF = CH ² , "HFO-1234yf") and / or 1, 3,3,3-tetrafluoropropene (CH2 = CFCF3, "HFO-1234ze"), and to compositions and uses thereof.

Background of the invention

Fluoropolymers such as polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), and polyvinylidene fluoride (PVDF) are well known for having excellent thermal, chemical, and weather resistance, along with favorable properties such as water and oil resistance. Unfortunately, the use of such fluoropolymers in coatings is difficult due to their poor solubility in industrial solvents, such as xylene and butyl acetate, which are typically used in the coating industry. Instead, more exotic solvents must often be used, which not only affect the economics of a coating, but can also present environmental problems due to, for example, the potential toxicity of exotic solvents.

Accordingly, there is a need to formulate alternative coatings that have superior performance properties, but can use inexpensive industrial solvents and are environmentally friendly.

In addition, the polymerization of fluorinated polymers presents a number of challenges, e.g. eg, as detailed in earlier application serial number 13 / 645,437 (now US Patent Publication No. 2013/0090439 A1), incorporated herein by reference. Although various types of polymerization methods for making tetrafluoropropene copolymers have been described in the earlier application serial number 13 / 645,437, applicants have further come to appreciate that these polymerization methods have undesirable aspects or limitations, and / or that polymers so produced can be formed with different and / or improved properties.

Consequently, applicants have come to appreciate the need to develop improved processes for making tetrafluoropropene copolymers having different and / or improved properties for uses in various applications.

Summary of the invention

According to a first aspect of the present invention, a curable fluorocopolymer can be formed by solution copolymerization of the monomers represented by (a), (b) and (c):

(a) 40 to 60 mole% tetrafluoropropene;

(b) 5 to 45% vinyl ether or vinyl ester or both, represented by the formula CH2 = CR1 -O (C = O) ^x R2 and CH2 = CR3-OR4 respectively, where R1 and R3 is hydrogen or a group methyl, and wherein R2 and R4 is an unsubstituted straight chain, branched chain or alicyclic alkyl group having 1 to 12 carbon atoms; Y

(c) 3 to 30% by mole of hydroxyalkyl vinyl ether, represented by the formula CH2 = C-R5-OR6,

wherein R5 is hydrogen or a methyl group, and R6 is a straight chain, branched or unsubstituted alicyclic alkyl group having hydroxyl groups.

According to a second aspect of the present invention, the tetrafluoropropene is selected from one or both of HFO-1234yf and HFO-1234ze. In accordance with the present invention, Applicants have discovered that environmentally friendly HFO-1234yf and HFO-1234ze can each and in combination be advantageously employed as fluorinated monomers for the production of polymeric coatings.

In accordance with a third aspect of the present invention, a product containing the curable fluorocopolymer has a solvent content of 15-50%, and preferably 15-25%, to provide a concentrated product that is economical to ship to the user of the product.

Detailed description of the invention

According to a preferred embodiment of the present invention, 40-60% by mole of tetrafluoropropene in the form of HFO-1234yf and / or HFO-1234ze is used as component (a), and most preferably, 45 to 55% in moles. If a mixture of HFO-1234yf and HFO-1234ze is used, the mixing ratio of HFO-1234yf and HFO-1234ze can be any ratio, but is preferably 0.3 to 0.7: 0.7 to 0.3.

A copolymer according to the present invention may contain vinyl ether units, vinyl ether units or a combination thereof as component (b). Preferably, 5 to 45% by mole is used, and most preferably, 25-45% by mole is used. Examples of vinyl ether include alkyl vinyl ethers such as methyl vinyl ether, ethyl, propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, and lauryl vinyl ether. Vinyl ethers including an alicyclic group can also be used, for example cyclobutyl vinyl ether, cyclopentyl vinyl ether and cyclohexyl vinyl ether. Examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl capronate, vinyl laurate, VEOVA-9 (vinyl versatate ester formed from a C9 carbocylic acid, produced by Momentive), VEOVA-10 (vinyl versatate ester formed from a C10 carbocylic acid, produced by Momentive) and vinyl cyclohexanecarboxylate.

Examples of the hydroxyalkyl vinyl ether of component (c) include hydroxylethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxypentyl vinyl ether, and hydroxyhexyl vinyl ether. Preferably 3 to 30% by mole are used, and most preferably, 5 to 20% by mole are used.

The fluorocopolymer is preferably produced in a solution polymerization system. Examples of solvents for solution polymerization include: esters, such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketones, such as acetone, methyl ethyl acetone, and cyclohexanone; aliphatic hydrocarbons, such as hexane, cyclohexane, octane, nonane, decane, undecane, dodecane, and mineral spirits; aromatic hydrocarbons, such as benzene, toluene, xylene, naphthalene, and solvent naphtha; alcohols, such as methanol, ethanol, tert-butanol, iso-propanol, ethylene glycol monoalkyl ethers; cyclic ethers, such as tetrahydrofuran, tetrahydropyran, and dioxane; fluorinated solvents, such as HCFC-225 and HCFC-141b; dimethylsulfoxide; and mixtures thereof.

Preferably, the polymerization is carried out in a range of -30 ° C to 150 ° C depending on the source of initiation of the polymerization and the type of the polymerization medium.

The copolymer of the present invention is preferably prepared by copolymerizing those monomers and having a number average molecular weight of 5,000 to 50,000, and more preferably 5,000 to 10,000. Preferably, the copolymer has a molecular weight distribution of 2 to 10, more preferably 2.5 to 8, and more preferably 3 to 6. When the number average molecular weight is less than 5000, the copolymer is inferior in weatherability and chemical resistance, and when more than 50000, high viscosities may cause operational difficulties.

The copolymer of the present invention has hydroxyl groups and is curable with a curing agent such as melamine resin curing agent, urea resin curing agent, polybasic acid curing agent, and an unblocked polyisocyanate curing agent. or a blocked polyisocyanate curing agent used for conventional thermoset acrylic coating. Examples of melamine resin curing agents include butylated melamine resin, methylated melamine resin, epoxymelamine resin, and the like. Examples of unblocked polyisocyanate include 2,4- and 2,6-diisocyanatotoluene (TDI), diphenylmethane-2,4'- and / or -4,4'-diisocyanate (MDI), 1,6-hexamethylene diisocyanate (HDI)) , 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), dicyclohexylmethane diisocyanate (H12MDI), 1,4-diisocyanatobutane, 2-methyl-1,5-diisocyanatopentane, 1,5-diisocyanate-2, 2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanate-decane, 1,3- and 1,4-diisocyanatocyclohexane, 1,3- and 1 , 4-bis- (isocyanatomethyl) -cyclohexane, 4,4'-diisocyanatodicyclohexylmethane, 1-isocyanato-1-methyl-4 (3) -isocyanatomethylcyclohexane (IMCI), bis- (isocyanatomethyl) -norbornane, 1,3- and 1 , 4-bis- (2-isocyanato-prop-2-yl) -benzene (TMXDI), 1,5-diisocyanatonaphthalene, 2,4'-, 4,4'-diisocyanatodiphenylmethane, and their dimers, trimers and polymers of the themselves. As for blocked polyisocyanate, preferred blocking groups used to block polyisocyanates include metal bisulfite, diethyl malonate (DEM) 3,5-dimethylpyrazole (DMP), methyl-ethylketoxime (MEKO), ecaprolactam (e-CAP), diisopropylamine, dimethylpyrazole, methyl ethyl ketoxime (butanone oxime), malonic acid diethyl ester, secondary amines, and triazole and pyrazole derivatives. When curing is carried out at normal temperature using polyisocyanate, it is possible to accelerate curing by adding a conventional catalyst such as dibutyl dilaurate.

Various solvents can be used for the preparation of paints or solution-type coatings with the copolymer of the present invention. Preferred solvents include aromatic hydrocarbons such as xylene and toluene; alcohols such as n-butanol; esters such as butyl acetate; ketones such as methyl isobutyl ketone and glycol ethers such as ethyl cellulose and various commercial diluents. When the copolymer of the present invention is used to produce a thermosetting composition for coating, a curing agent such as a melamine type curing agent, a urea type curing agent, a polybasic acid type curing agent, a Polyisocyanate type curing agents or the like are mixed simultaneously in the above-mentioned mixing step to produce a single component type coating.

On the other hand, when the composition is a normal temperature setting type coating using a polyisocyanate, the curing agent component is prepared separately to provide a two component type coating. In this case, the coating can be cured at room temperature for several hours to several days, and it has good properties by controlling the type of isocyanate and catalyst and their amounts to be added, the concentration of the copolymer, the content of the hydroxyalkyl. vinyl ether in the copolymer, and the like.

When the copolymer of the present invention is used as a resin for painting or coating, it is possible to form, under mild conditions, a film having excellent finish hardness and gloss, flexibility, chemical resistance, stain resistance and weatherability. . Such films are useful not only as a coating for pre-coated galvanized steel, colored aluminum plates and aluminum frames, but also as paint-in-place paint that cannot be thermally dried. Paint or coating can be used for various substrates, including: metallic substrates; inorganic substrates such as glass, cement and concrete; organic substrates, eg, plastics (such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, nylon, acryl polyester copolymer, ethylene-polyvinyl alcohol, vinyl chloride, vinylidene chloride), and wood materials. Specific applications for paint or coating include, but are not limited to, aluminum pool liner, colored glass liner intended for exterior use, and cement shingle liner used for roofs.

The present invention is further illustrated by the following non-limiting examples.

Example 1

19.0 g of butyl acetate, 9.5 g of ethyl vinyl ether, 20.8 g of VEOVA-9, 8.0 g of hydroxybutyl vinyl ether and 0.62 g of tert-butyl peroxypivalate were charged in an autoclave 300 ml stainless steel tube equipped with a stirrer. The mixture was solidified with liquid nitrogen and deaerated to remove dissolved air. Then, 50 g of 1,3,3,3-tetrafluoropropene was added to the mixture, and the mixture was gradually heated to 65 ° C in an autoclave. The mixture was stirred for 18 hours. After the autoclave was cooled to room temperature, unreacted monomers were purged and the autoclave was opened. The excess solvent was removed by evaporation.

Yield 92%; Tg (glass transition temperature) of the final copolymer = 15 ° C; Mn = 7348; Mw = 13789; Mw / Mn = 1.87; final polymer concentration = 74.7%; viscosity <500 cps.

Example 2

20.0 g of butyl acetate, 9.1 g of ethyl vinyl ether, 6.0 g of vinyl acetate, 6.7 g of hydroxybutyl vinyl ether and 0.4 g were charged. of tert-butyl peroxypivalate in a 300 ml stainless steel autoclave equipped with a stirrer. The mixture was solidified with liquid nitrogen and deaerated to remove dissolved air. Then, 40 g of 2,3,3,3-tetrafluoropropene was added to the mixture, and the mixture was gradually heated to 65 ° C in an autoclave. The mixture was stirred for 18 hours. After the autoclave was cooled to room temperature, unreacted monomers were purged and the autoclave was opened. The excess solvent was removed by evaporation.

Yield 91%; Final copolymer Tg = 11 ° C; Mn = 5314; Mw = 12646; Mw / Mn = 2.38; final polymer concentration = 73.8%; viscosity <600 cps.

Example 3

20.0 g of butyl acetate, 8.0 g of ethyl vinyl ether, 17.4 g of VEOVA-9, 6.7 g were charged. of hydroxybutyl vinyl ether and 0.63 g. of tert-butyl peroxypivalate in a 300 ml stainless steel autoclave equipped with a stirrer. The mixture was solidified with liquid nitrogen and deaerated to remove dissolved air. Then, 60 g of 1,3,3,3-tetrafluoropropene was added to the mixture, and the mixture was gradually heated to 65 ° C in an autoclave. The mixture was stirred for 18 hours. After the autoclave was cooled to room temperature, unreacted monomers were purged and the autoclave was opened. The excess solvent was removed by evaporation.

Yield 93%; Final copolymer Tg = 32 ° C; Mn = 7136; Mw = 24103; Mw / Mn = 3.37; final polymer concentration = 81.1%; viscosity <700 cps.

Example 4

20.0 g of butyl acetate, 8.2 g of ethyl vinyl ether, 22.3 g of VEOVA-9, 3.4 g of hydroxybutyl vinyl ether and 0.66 g of tert-butyl peroxypivalate were charged in an autoclave 300 ml stainless steel tube equipped with a stirrer. The mixture was solidified with liquid nitrogen and deaerated to remove dissolved air. Then, 50 g of 1,3,3,3-tetrafluoropropene was added to the mixture, and the mixture was gradually heated to 65 ° C in an autoclave. The mixture was stirred for 18 hours. After the autoclave was cooled to room temperature, unreacted monomers were purged and the autoclave was opened. The excess solvent was removed by evaporation.

85% yield; Final copolymer Tg = 12 ° C; Mn = 4640; Mw = 8079; Mw / Mn = 1.74; final polymer concentration = 78.1%; viscosity <600 cps.

Example 5

30.0 g of butyl acetate, 7.6 g of ethyl vinyl ether, 18.4 g of VeoVa-9, 6.7 g of hydroxybutyl vinyl ether and 0.60 g of tert-butyl peroxypivalate were charged into an autoclave 300 ml stainless steel tube equipped with a stirrer. The mixture was solidified with liquid nitrogen and deaerated to remove dissolved air. Then, 60 g of 1,3,3,3 tetrafluoropropene was added to the mixture, and the mixture was gradually heated to 65 ° C in an autoclave. The mixture was stirred for 18 hours. After the autoclave was cooled to room temperature, unreacted monomers were purged and the autoclave was opened. The excess solvent was removed by evaporation.

82% yield; Final copolymer Tg = 22 ° C; Mn = 7640; Mw = 17620; Mw / Mn = 2.31; final polymer concentration = 71.7%; viscosity <600 cps.

Application example

26.1 g of the resulting copolymer were dissolved in 17.9 g of butyl acetate, and then 22.3 g of titanium oxide were mixed. The mixture was mixed for 1 hour with a paint shaker, then further mixed with 14.8 g of DESMODUR BL4265 and 0.3 g of dibutyl dilaurate (1% concentration). The mixture was then used to coat an aluminum substrate. Approximately 72 hours later, the physical properties of the surface were tested.

The gloss (ISO 2813) of the surface = 70 (20 ° C); Hardness (Pencil Test; ASTM D3363) = 3H; Flexibility (ASTM D4145) = 3T; Adhesion (ASTM D3359) = 5B.

From the foregoing, it will be appreciated that, although specific examples have been described herein for illustrative purposes, various modifications can be made without departing from the spirit or scope of this disclosure. Therefore, it is intended that the above detailed description be considered illustrative rather than limiting, and that it is understood that the following claims, including all equivalents, are intended to clearly state and vindicate the claimed subject matter.

Claims (8)

1. A copolymer comprising: (a) a first unit comprising a polymerized monomer selected from the group consisting of 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene; (b) a second unit comprising a polymerized monomer selected from the group consisting of vinyl esters and vinyl ethers; wherein the vinyl esters and vinyl ethers are of the formula CH2 = CR1 -O (C = O) R2 and CH2 = CR3-OR4, respectively, where R1 and R3 are hydrogen or a methyl group, and where R2 and R4 is a straight chain, branched or unsubstituted alicyclic alkyl group having 1 to 12 carbon atoms; Y (c) a third unit comprising a polymerized monomer comprising a vinyl ether containing a hydroxyl group of the formula CH2 = C-R5-OR6, wherein R5 is hydrogen or a methyl group, and R6 is a chain alkyl group unsubstituted linear, branched or alicyclic having a hydroxyl group. 2. The copolymer of claim 1, wherein the copolymer comprises 40 to 60% by mole of said first unit. 3. The copolymer of claim 2, wherein the copolymer comprises 5 to 45% by mole of said second unit, wherein said second unit is selected from the group consisting of alkyl vinyl ethers, vinyl esters and mixtures thereof. 4. The copolymer of claim 3, wherein the copolymer comprises 3 to 30% by mole of said third unit, wherein said third unit consists of hydroxyalkyl vinyl ethers. 5. A process for the production of the copolymer of claim 1, wherein the monomers are polymerized in a solution to produce the copolymer of claim 1. 6. A composition comprising at least 70% by weight of the copolymer of claim 1. 7. The composition of claim 6, wherein the composition comprises at least 80% by weight of the copolymer. 8. The composition of claim 6, wherein the composition comprises 15-25% by weight of solvent.